code: def testRMSEMetric(self):
      predictions = np.full((10, 1), 1)  # All 1's
      targets = np.full((10, 1), 3)  # All 3's
      expected = np.sqrt(
          np.mean((predictions - targets) ** 2)
      )  # RMSE = 2.0
      with self.test_session() as session:
          rmse, _ = metrics.padded_rmse(
              tf.constant(predictions, dtype=tf.int32),
              tf.constant(targets, dtype=tf.int32),
          )
          session.run(tf.global_variables_initializer())
          actual = session.run(rmse)
      self.assertEqual(actual, expected)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  from tensor2tensor.utils import metrics
  import tensorflow.compat.v1
label_desc: Use image node_id 8 for calling the MetricsTest obj's underlying member method code with example usage: obj.testRMSEMetric() without return types